The Sediments of Time

by Meave Leakey

  Over three months in 1951, Mary, with the help of Louis and an Italian assistant, Giuseppe Della Giustina, had painstakingly traced these evocative images from the rock faces at 186 sites in central Tanzania. The original reproductions had been stored away for thirty years until I came across them while helping Mary clear her office. I was astonished at the detail in these paintings. In 43 paintings, 1,600 figures were recorded. I was enthralled by these lifelike images and the scenes depicted in this art, and I persuaded Mary that they needed to be shared with a wider audience. She agreed to put together a book but only if I helped. I questioned Mary about her interpretations of their meanings, and she would always have an answer to my many questions.

  “Mary, look how they have picked out and exaggerated the essential characters that make it easy to identify the species being painted—these snakes have been given so many coils, and the antelope horns have an exaggerated number of spirals, the eland have exaggerated dewlaps and the cats long thin tails—but whatever do you think these people are doing?”

  “They seem to dancing in a river to celebrate some event,” Mary responded. “One of my favourite figures is this pipe player with music falling from his pipe.”

  I pulled out another painting. “Mary—in this painting, see how these figures are excitedly dancing and cavorting around an elephant that they appear to have caught in a trap.”

  * * *

  WE WERE BOTH INTRIGUED by the scenes depicted and the lifelike images projected onto the uneven rock faces. They were accurately drawn and gave insights into the lives of these ancient people. The poignant images of daily life—hunting, playing music, seeing herds of game—evoke the perennial questions motivating our search: what connects, and sets apart, modern humans from our ancient ancestors? This time with Mary sharing our interpretations of images’ possible meaning was profoundly rewarding both professionally and from a personal standpoint as I got to appreciate my mother-in-law for all the facets of her complex and special character.

  After the horrors of the past year, we resumed the threads of our lives at a slightly more measured pace than we had lived in the 1970s. Although very full, these years were uneventful from a personal perspective—no births, no deaths, and no life-threatening illnesses. The dictates of a school schedule meant that I spent less time in the field, and as I took over as head of palaeontology at the museum in 1982, I had an increasingly large load of office work. Spending more time in Nairobi meant that I was also more directly involved in writing the scientific papers on the fossils, often collaborating with Alan Walker. But Richard, with his new lease on life, took the fieldwork farther afield in terms of the geological age span and in geographical distance from our Koobi Fora base camp. As Richard and Kamoya explored far and wide throughout the 1980s, they discovered many new sites on both the east and west sides of the lake. Unlike the sites we had concentrated on in the 1970s, which were all between two and one million years old, these new sites ranged in age from thirty million years to one million years old. This period spans almost the entire evolution of apes and hominins.

  Our exploration of the sites on the west side of the lake began in 1981. Because these sites cover a much longer geological time frame, they were key to amass, piece by piece, an unprecedented knowledge of the evolutionary history of the vast Turkana Basin. As expected, our fossil collection of human ancestors steadily grew.

  In 1983, Richard and I visited an eighteen-million-year-old site called Buluk and had a truly memorable weekend. On the first day, we had gone for a walk across the exposures. It was very hot, and Richard was in the lead, walking extremely fast as usual. Little Samira simply could not keep up, so the two of us were trailing the others. It turned out to be the very best place to be. Everybody else walked straight past the discovery that was awaiting us—beautifully preserved parts of both the upper and lower jaws of an ancient ape, which must have tumbled out of the bank above the path during the last heavy rains. I knew at once that I had never seen anything that looked quite like it. Sure enough, it was completely new to science! Richard and the others retraced their steps, thrilled about the discovery but privately chagrined to have missed such an important find. We collected the precious fossil, wrapping it in loo paper and recording its exact location on the aerial photo with a pinprick. But no sooner had we set off again, with Samira and me still lagging far behind, than we came upon something else that everybody had narrowly missed stepping on. But this was alive and much deadlier. It was an agitated carpet viper hissing and writhing in the sand and ready to strike!

  The period before the origins of our hominin lineage is known as the Miocene (lasting between twenty-three and five million years ago), a time when many different apes existed in both Africa and Eurasia. Most of the ancient African ape fossils known in 1983 originated from two islands on Lake Victoria, Rusinga and Mfangano, which Louis and Mary Leakey had explored in the 1940s. There are so many apes known from these two rich Early Miocene sites that we had not been expecting a new ancient ape to be found at Turkana. But the ape that Samira and I stumbled upon looked so different that we were compelled to search in other sites of this age in Turkana as well.

  Richard asked Kamoya and the crew to stop off at site on the western shore called Kalodirr on their return overland to Nairobi, a site Richard had noticed some time before from the air. To his astonishment, Kamoya turned up in his office some days later grinning broadly and carrying a precious bundle. During his lightening visit to Kalodirr, he had found a delightful little skull completely new to science.

  We planned a longer visit to Kalodirr the following January. For once, we had funds to do a second field season. A certain Mr. Brownlee had been persistently trying to see Richard at the museum on a day when Richard had left clear instructions that he was not to be disturbed. But Mr. Brownlee was not to be deterred. In contrast to the usual run of visitors who urgently requested some form of assistance, Mr. Brownlee wanted to give us a very generous gift of one hundred thousand dollars for our research. Mr. Brownlee had made his money inventing medical equipment, but his hobby was studying ants. He came to Kalodirr to visit for a few days, and I remember spending an extraordinary hour with him one very hot lunchtime while we waited for Richard and the crew to return. Mr. Brownlee wanted to persuade me that different ants taste different and that this was a sure-fire method of identification. I was happy to oblige this kind benefactor, so we sampled ants. A most unusual hors d’oeuvre!

  This second visit to Kalodirr produced many new species of animals. There were several new examples of the ape we had found at Buluk, which we named Afropithecus turkanensis. We gave the skull that Kamoya brought to Nairobi the name Turkanapithecus, and a third brand-new fossil ape also cropped up. We called this tiny monkey-sized creature Simiolus enjiessi as a nod to the National Geographic Society, which had funded so much of our research over the years. There was an even greater diversity of early apes than we had imagined. One ape would eventually split from the others to give rise to the human lineage—so all these different early examples are of considerable interest. But the subsequent period of prehistory, called the Late Miocene, is poorly recorded in the sediments of the Turkana Basin. We simply don’t know what happened next or where these early apes led. Indeed, we know very little about any of the apes that evolved from these ancient creatures, let alone the enigmatic species that led to humans.

  During the school holidays in the summer of 1984, Kamoya and his team completed their survey of the Miocene sediments and moved on to search younger exposures to the north of Lomekwi on the west side of the lake. I was at Koobi Fora with my girls for their first proper excavation—an enormous giant tortoise that must have died when it somehow landed upside down and was unable to right itself. This spectacular specimen remains on exhibit to this day and is one of the most impressive field exhibits we have in Kenya, both because of its size (the carapace is nearly two metres) and completeness. The girls could sit quite comfortably inside the inverted shell as they wor
ked and had ample room to spare. After work, we’d all cool down in the lake and enjoy Koobi Fora’s majestic beauty.

  All this came to an abrupt halt one Sunday when Kamoya took a short Sunday stroll from the camp across the lake and stumbled upon an unpromising matchbox-sized piece of skull. It soon became clear that the little skull fragment was just the beginning of a miraculous and groundbreaking discovery as fragment after fragment followed that first piece out of the rocky ground.

  Once the enormity of what was happening became apparent, Richard ferried us over the lake to join in the excitement on the west side. We flew into a short airstrip close to camp that gave the uncomfortable sensation of landing on a very narrow aircraft carrier because it was built on a skinny plateau that dropped steeply off on all sides. The site was on the bank of a tributary running into the Nariokotome sand river and was a short walk from a lovely shady camp set among the acacia and doum palms fringing the river.

  “Come and see the site!” Richard said enthusiastically before my feet had even touched the ground. The field crew, under his supervision, had begun the excavation.

  “What are you going to do about that tree?” I immediately asked, pointing to a small toothbrush tree right where the skull fragments were being retrieved.

  “The tree stays. Removing it might damage anything in the ground that we can’t see!”

  “Humph. Or you might not see the pieces you need to remove without addressing the tree!” I retorted.

  I was soon caught up in the thrill of what was unfolding. Back in camp, under an improvised canvas laboratory tent, there were already a number of wooden trays with numerous fossils in them. Not all of these were hominid as we collected every bone fragment we could find, and these would later help us understand the setting and circumstances at the time the individual died. The thrill of finding a hominin fossil is hard to describe. But to witness an outpouring of bones completely new to science and in immaculate condition is something quite extraordinary. Camp was buzzing with excitement and an air of anticipation as to what might follow.

  Back in camp, Alan Walker and I gradually reassembled a complete skull with a face. Richard oversaw the excavation work at the site, and he and the field crew uncovered more skull fragments, the mandible, and then, to our astonishment, the first bones of the skeleton. Here, for the first time, were well-preserved elements of a Homo erectus skeleton associated with a cranium and mandible.

  As the scale of the discovery became more obvious, Richard invited his mother, the matriarch of proper excavation techniques, to observe our efforts. Far from impressed, she soon was criticizing him and Kamoya for their sloppy work. “Do you think you are still digging potatoes?” she chastised Kamoya with her fiercest glare. Kamoya and Nzube grinned ruefully, having cut their teeth on Mary’s excavations in Olduvai and endured many similar tongue-lashings in the past. Measuring tape and string in hand, Mary soon imposed her meticulous standards and grid method for plotting the precise position of each bone fragment. Stakes were placed precisely in the ground to form a level grid, and as the excavation got deeper, the elevation of each grid was plotted so that the exact layer the bones are eroding out of could be recorded. This method is still our standard practice today, and her input would later form a key contribution for piecing together the environment and circumstances when the fossil individual died.

  We employed a number of local boys on their school holidays to help with the multitude of camp chores entailed in running such a big excavation. Louise and Samira spent long hours with the Turkana children, all enthusiastic workers enjoying the unprecedented and plentiful meals along with their salaries. These children were also hungry for any opportunities to learn, their school having only minimum facilities. They eagerly pored over the girls’ old schoolbooks, National Geographic children’s magazines, and anything my girls could find for them to read. Louise and Samira taught them card games and in turn learned traditional Turkana games. The children remember these field seasons as being far more fun than usual—instead of being confined in silence to our private banda at Koobi Fora, out of sight and earshot of the “very important scientists” with whom they were only rarely allowed to mix, they suddenly had their own companions.

  In 1985, when Louise was twelve, she was given greater responsibility for maintaining the camp drinking-water supply by being allowed to drive all the kids to the nearby waterhole. Each day, it took them precisely four hours to fill up the drums of drinking water using an old Kimbo tin (a type of vegetable shortening we used for cooking) to scoop the clear water out of the hole dug into the sand river. One tin at a time, Samira, who was the smallest, would patiently fill a bucket that was then passed up the chain of children to the biggest and strongest of them, Christopher, who was manning the drum (Christopher would later become camp cook when he left school). The whole operation was completed with a great deal of noise, singing, and storytelling, especially during the frequent breaks they were obliged to take while they waited for the depleted water in the waterhole to slowly rise again. Louise was barely able to see over the steering wheel, but she quickly learned to drive in difficult terrain. The children were proud to at last be given a modicum of responsibility and play a role in helping facilitate the historic find that was unfolding in camp.

  Meanwhile, the size of the excavation continued to grow as tons of rock were gently removed piece by piece from the site. All the excavated soil and pebbles from the layers containing bone fragments had to be sieved and picked over to make sure nothing was overlooked. The soil was placed in a wooden frame with handles and a wire mesh bottom. Two people vigorously shook this sieve to remove the dust and smallest particles, and the rest was looked over meticulously before being discarded. This process is accomplished much more effectively when the material is wet because the fossils stand out much more distinctively. With Samira and the Turkana schoolboys as helpers, Louise drove the pickup truck to the lakeshore and dropped off sacks of sediment for the sievers to pick through. After trying their hand with the sieve and taking an obligatory and wonderfully refreshing dip in the lake, the children then returned with the washing water for camp.

  Over the course of five years, more and more bones were exposed—arm bones, leg bones, ribs, vertebrae, and a pelvis. But the hands and feet remained hidden. Each year, during the last week of fieldwork, a bone would turn up in the far back corner suggesting that perhaps these precious missing elements were just under the next part of the bank. The excavation was then extended into a high bank, which meant that the tons of soil covering the horizon in which the bones were buried had to be removed.

  At the end of the 1987 season, we accepted defeat and gave up the hunt for the elusive hand and foot bones. The cost of continuing the enormous excavation outweighed the remote chance that we might ever find them. But even without these missing appendages, we had an amazingly complete skeleton, skull, and mandible of a single individual. This fossil is a unique discovery—the skeleton of a child, seven to eleven years old, who lived around 1.5 million years ago. It is known all over the world as the Nariokotome Boy, or the Turkana Boy, and is celebrated today by a monument and bronze replica at the site where it was found. The completeness of the boy’s skeleton would permit us to make many deductions hitherto impossible from single limb bones or unassociated skulls. The wealth of information contained in these bones would take many years and many different specialists to uncover, but the search for our last ancestor had just taken a quantum leap forward.

  Some of the most iconic finds we made in the 1970s and 1980s (not drawn to scale).

  4

  Changing of the Guard

  Late on a Thursday afternoon in April 1989 shortly after the one o’clock news bulletin on the state radio (which neither of us was in the habit of listening to), Richard received an extraordinary phone call from a colleague.

  “Congratulations!” began the colleague. “Thank you. Whatever for?” asked a bewildered Richard. “You must be joking!” replied the now
equally bewildered colleague. “No. What have I done?” queried Richard bemusedly. Thus Richard came to know that he had been handpicked by President Daniel arap Moi to head the body overseeing Kenya’s national parks and reserves, the Wildlife Conservation and Management Department, effective immediately. I didn’t believe it either when he called me shortly afterwards to share the news.

  Richard’s disbelief was not only caused by this unorthodox method of learning about his new job. He had been engaged in a ferocious public spat with high-ranking government officials during the preceding weeks, so the announcement was a bold and unexpected step by President Moi. At the time, elephants were being slaughtered in increasing and alarmingly high numbers, yet the government had been categorically denying that poaching was a serious issue. Never one to hide his head in the sand, Richard had launched a scathing attack on the minister responsible for wildlife and tourism, George Muhoho, going so far as to allege a high-level government cover-up of the scale of poaching.

  This must be seen in its proper context: in 1989 Kenya, multiparty politics had not yet made its debut. Put plainly, a civil servant did not under any circumstance openly and publicly challenge the government, which was synonymous with the party line. With the whiff of corruption added to this scandalous departure from convention, the media had pounced on the story. As a consequence, the decimation of Kenya’s elephant population was hitting the headlines daily, and gruesome images of the great hulking carcasses, their tusks violently hacked away, were regularly splattered across the front pages. The latest salvo from Right Honourable Minister Muhoho had just dismissed Richard’s “cheeky white mentality,” so the last thing we had been expecting was for Richard to be the very one tasked by the government to sort out the problem. But strange and unexpected things happen in life.